My alero has a 3400 currently and is running pretty high temps,its been running 235 or around and at times gets in the red,figured bad gaskets car has 167,000 miles,I want to ditch the 3.4 and may go to a 3.1 for temp reasons or better yet top swap it with a 3.5,ran across a website that talks about it,can use my wiring harness and current ecm,has anyone did it successfully,what can I run into,are blocks the same?